The older half-brother of North Korean leader Kim Jong-un was reportedly assassinated at Kuala Lumpur International Airport.

A TV screen shows a picture of Kim Jong Nam, the older brother of North Korean leader Kim Jong Un, at the Seoul Railway Station in Seoul, South Korea, Tuesday, Feb. 14, 2017. Malaysian officials say a North Korean man has died after suddenly becoming ill at Kuala Lumpur's airport.

February 14, 2017
—The older half-brother of North Korea's Supreme Leader died Tuesday in a Malaysian airport under mysterious circumstances, South Korean and Malaysian news outlets reported, in what the US government believes may have been a murder carried out by North Korean agents.

The Royal Malaysian Police issued a statement identifying the deceased as a 46-year-old North Korean man, Kim Chol – an alias that South Korean officials say was being used by Kim Jong-nam.

The man had been waiting to board a flight to Macau when, according to police official Fadzil Ahmat, “a woman came from behind and covered his face with a cloth laced with a liquid,” as he told Bernama, the Malaysian state news agency.

A South Korean news channel citing government sources had reported, however, that Kim Jong-nam had been attacked by two female assailants who pricked him with poisoned needles before fleeing the airport in a taxi.

While the exact events remain unclear, Malaysian police and government officials from South Korea have confirmed that Kim Jong-nam was killed. The brother of the North Korean leader died in an ambulance en route to a hospital, after an incident occurred while waiting to board a flight to Macau.

Outside analysts had once assumed that Kim Jong-nam, the eldest son of former leader Kim Jong-il, could be the intended heir after his father, whose own father, Kim Il-sung, founded the Democratic People's Republic of Korea after World War II. In 2016, however, Kim Jong-un's aunt, who has lived in the US for nearly two decades, told The Washington Post that the younger son had been designated the next leader when he was still a child.

“Kim Jong Nam was involved in some funny business,” Michael Madden, the editor of the website North Korea Leadership Watch, told the Post. He was rumored to have worked in computing in North Korea and money laundering operations across Southeast Asia, according to the Post.

In 2001, Kim Jong-nam was caught with his wife and son trying to enter Japan on fake Dominican Republic passports. When questioned, he told authorities he was planning to visit Tokyo Disneyland. Since then, however, he was believed to have spent much of his time living abroad.

In 2013, Kim Jong-un ordered the execution of their uncle and mentor, Chang Song-thaek, previously the second most powerful man in the country – and to whom Kim Jong-nam was particularly close.

Since then, according to the Post, analysts had suspected that China had been keeping the elder brother as a possible replacement for Kim Jong-un, should relations between the two countries continue becoming further strained.

The US government believes that Kim Jong-nam's death was likely the work of North Korean agents, a government source told Reuters on Tuesday. North Korea does have a history of sending agents overseas to perform kidnappings, attacks, and assassinations, the BBC reports.

Ahmat, the Malaysian police official, told reporters that the cause of death had not yet been determined.

"So far there are no suspects, but we have started investigations and are looking at a few possibilities to get leads," he told Reuters.